Revert legend when results are grouped

Revert legend when results are grouped

Since Ifecaaff572, legend was using position: absolute when results are
grouped by page. Most users found such behavior annoying and unexpected,
so positioning is being reverted to previous state.

Only change besides reverting is preventing collapsed legend to push
away the surrounding results. Without that, we would have scenarios
where legend is expanded and collapsed, but results are pushed away as
if legend is still expanded.

Bug: T182156
Bug: T184165
Change-Id: I5adb7e1cb793ec30fba9d5d9674a7fa294d9a3a5